It is Kevin's sixth child, as he also has two children with ex-girlfriend Shar Jackson, two boys Sean-Preston and Jayden with his ex-wife Britney Spears, and another daughter with wife Victoria.
His wife Victoria Prince posted several snaps of the little girl, revealing the baby has a head full of dark hair.
Victoria also posted a picture of Sean-Preston and Jayden taking a look at their new half-sister as they are joined by Kevin and Victoria's first daughter, Jordan.
The pair revealed their adorable nicknames for the family, as Victoria hashtagged the family in her pictures.
"Time with daddy! #tbt at the hospital when Peyton was 1 day old! @federline4real#thefedz#jordybear#jboogy#pdubs#babypeyton," she captioned a shot of her family, with Kevin, Jordan, Jayden, Sean-Preston and baby Peyton all being bestowed with nicknames.
In an earlier picture Kevin confirmed the pair had welcomed their daughter with a shot of a floral arrangement, and the caption: "Words cannot express the joy my children bring me."
Kevin Federline posted this snap of his two children together
"We are very excited to welcome the newest member of our family. I love you with all my heart @crownv_16," Kevin added, tagging Victoria.
Victoria and Kevin married in August 2013 after a surprise proposal during a "work trip" to Las Vegas.
Getting down on one knee, he said, "Victoria Prince, will you marry me in two days, infront of 30 of our closest family and friends?"
The couple, who had been dating since 2008, tied the knot in an intimate ceremony in the penthouse of the Hard Rock Hotel.